首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   479篇
  免费   12篇
  2021年   11篇
  2019年   20篇
  2018年   10篇
  2017年   10篇
  2016年   11篇
  2015年   11篇
  2014年   9篇
  2013年   96篇
  2011年   4篇
  2009年   5篇
  2008年   5篇
  2007年   5篇
  2006年   5篇
  2005年   9篇
  2004年   8篇
  2003年   6篇
  2002年   6篇
  2001年   4篇
  2000年   7篇
  1999年   4篇
  1998年   8篇
  1997年   15篇
  1996年   7篇
  1994年   10篇
  1992年   4篇
  1991年   13篇
  1990年   4篇
  1989年   7篇
  1988年   7篇
  1987年   14篇
  1986年   8篇
  1985年   6篇
  1984年   5篇
  1983年   8篇
  1982年   8篇
  1981年   5篇
  1980年   7篇
  1979年   11篇
  1978年   7篇
  1977年   8篇
  1976年   7篇
  1975年   7篇
  1974年   7篇
  1973年   12篇
  1972年   6篇
  1971年   6篇
  1970年   7篇
  1969年   6篇
  1968年   5篇
  1967年   5篇
排序方式: 共有491条查询结果,搜索用时 15 毫秒
481.
482.
483.
This paper investigates civil conflict as a product of the survival strategies of African leaders. Specifically, the paper offers a theory of risk substitution that predicts coup-fearing leaders will undermine the military effectiveness of the state when making an effort to extend their own tenure. While ‘coup-proofing’ practices have often been noted as contributors to political survival, considerably less attention has been paid to the influence of these strategies on other forms of conflict. Utilising data from a number of cross-national datasets, the analyses show that having a higher number of ‘coup-proofing’ counterweights significantly worsens a state's civil conflict prospects. A brief consideration of multiple episodes of conflict further suggests that in addition to coup-proofing undermining the counterinsurgency capacity of the state, some leaders are simply indifferent to – or can even potentially benefit from – the existence of an insurgency.  相似文献   
484.
We consider a manufacturer (i.e., a capacitated supplier) that produces to stock and has two classes of customers. The primary customer places orders at regular intervals of time for a random quantity, while the secondary customers request a single item at random times. At a predetermined time the manufacturer receives advance demand information regarding the order size of the primary customer. If the manufacturer is not able to fill the primary customer's demand, there is a penalty. On the other hand, serving the secondary customers results in additional profit; however, the manufacturer can refuse to serve the secondary customers in order to reserve inventory for the primary customer. We characterize the manufacturer's optimal production and stock reservation policies that maximize the manufacturer's discounted profit and the average profit per unit time. We show that these policies are threshold‐type policies, and these thresholds are monotone with respect to the primary customer's order size. Using a numerical study we provide insights into how the value of information is affected by the relative demand size of the primary and secondary customers. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007  相似文献   
485.
Designing Code Division Multiple Access networks includes determining optimal locations of radio towers and assigning customer markets to the towers. In this paper, we describe a deterministic model for tower location and a stochastic model to optimize revenue given a set of constructed towers. We integrate these models in a stochastic integer programming problem with simple recourse that optimizes the location of towers under demand uncertainty. We develop algorithms using Benders' reformulation, and we provide computational results. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007  相似文献   
486.
487.
ABSTRACT

This article focuses on the final years of South Africa’s nuclear-weapon program, particularly on the decision-making process leading up to the signature of the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) by the South African government in 1991. In August 1988, after two decades of defiance, negotiations between the apartheid government and the NPT depository powers (the United Kingdom, the United States, and the Soviet Union) ensued at the International Atomic Energy Agency (IAEA) in Vienna. Despite South Africa being the only state to give up its indigenously developed nuclear weapons and subsequently join the nonproliferation regime, little is known about how the national position on NPT accession and IAEA safeguards evolved. Research carried out in multiple archives using hitherto untapped primary sources and interviews with key actors from several countries show how domestic and regional political dynamics influenced Pretoria’s position on entering the nonproliferation regime. In the process, the F.W. de Klerk government managed to skillfully exploit international proliferation fears to advance its own agenda, thereby connecting South African NPT accession with that of the neighboring Frontline States coalition of Angola, Mozambique, Tanzania, Zambia, and Zimbabwe.  相似文献   
488.
489.
490.
ABSTRACT

This paper examines the career of one of the most notable of Chinese state officials in the mid-nineteenth century, General Zuo Zongtang (1812–1885) at a time when the Qing Empire was beset by enemies on all sides along with the massive Taiping Rebellion (1851–65). The paper explores how Zuo created a coherent and flexible counter-insurgency doctrine that underpinned his suppression of the Taipings, the Nian, Muslim rebels of the northwest and the defeat of a massive Sufi revolt in Central Asia. The paper also shows how Zuo helped convince the Russians to return territory they occupied in Central Asia, thereby preserving the territorial integrity of the Qing Empire in the region.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号